To make a long story short, McPhee describes two things: how Switzerland requires military service from every able-bodied male Swiss citizen — a model later emulated and expanded by Israel — and how the Swiss military has, in effect, wired the entire country to blow in the event of foreign invasion. To keep enemy armies out, bridges will be dynamited and, whenever possible, deliberately collapsed onto other roads and bridges below; hills have been weaponized to be activated as valley-sweeping artificial landslides; mountain tunnels will be sealed from within to act as nuclear-proof air raid shelters; and much more.

First, a quick look at the system of self-demolition that is literally built into the Swiss national infrastructure:

To interrupt the utility of bridges, tunnels, highways, railroads, Switzerland has established three thousand points of demolition. That is the number officially printed. It has been suggested to me that to approximate a true figure a reader ought to multiply by two. Where a highway bridge crosses a railroad, a segment of the bridge is programmed to drop on the railroad. Primacord fuses are built into the bridge. Hidden artillery is in place on either side, set to prevent the enemy from clearing or repairing the damage.

Further:

Near the German border of Switzerland, every railroad and highway tunnel has been prepared to pinch shut explosively. Nearby mountains have been made so porous that whole divisions can fit inside them. There are weapons and soldiers under barns. There are cannons inside pretty houses. Where Swiss highways happen to run on narrow ground between the edges of lakes and to the bottoms of cliffs, man-made rockslides are ready to slide.

The impending self-demolition of the country is "routinely practiced," McPhee writes. "Often, in such assignments, the civilian engineer who created the bridge will, in his capacity as a military officer, be given the task of planning its destruction."

But this is where a weirdly fascinating, George Dante-esque artifice begins. After all, McPhee writes, why would Switzerland want anyone to know where the dynamite is wired, where the cannons are hidden, which bridges will blow, or where to find the Army's top secret mountain hideaways and resupply shelters? But if you look closely, you start to see things.

Through locked gates you see corridors in the sides of mountains-going on and on into the rock, with alight in the ceiling every five meters and far too many to count... Riding around Switzerland with these matters in mind-seeing little driveways that blank out in mountain walls, cavern entrances like dark spots under mountainside railroads and winding corniches, portals in various forms of lithic disguise-you can find it difficult not to imagine that almost anything is a military deception, masking a hidden installation.

Indeed, at one point McPhee jokes that his local guide in Switzerland "tends to treat the army itself as if it were a military secret."

McPhee points to small moments of "fake stonework, concealing the artillery behind it," that dot Switzerland's Alpine geology, little doors that will pop open to reveal internal cannons and blast the country's roads to smithereens. Later, passing under a mountain bridge, McPhee notices "small steel doors in one pier" hinting that the bridge "was ready to blow. It had been superceded, however, by an even higher bridge, which leaped through the sky above-a part of the new road to Simplon. In an extreme emergency, the midspan of the new bridge would no doubt drop on the old one." It's a strange kind of national infrastructure, one that is at its most rigorously functional — one that truly fulfills its promises-when in a state of cascading self-imposed collapse.

I could easily over-quote my way to the end of my internet service here, but it's a story worth reading. There are, for instance, hidden bomb shelters everywhere in an extraordinary application of dual-use construction. "All over Switzerland," according to McPhee, "in relatively spacious and quiet towns, are sophisticated underground parking garages with automatic machines that offer tickets like tongues and imply a level of commerce that is somewhere else. In a nuclear emergency, huge doors would slide closed with the town's population inside."

Describing titanic underground fortresses — "networks of tunnels, caverns, bunkers, and surface installations, each spread through many tens of square miles" — McPhee briefly relates the story of a military reconnaissance mission on which he was able to tag along, involving a hydroelectric power station built inside a mountain, accessible by ladders and stairs; the battalion tasked with climbing down into it thus learns "that if a company of soldiers had to do it they could climb the mountain on the inside."

In any case, the book's vision of the Alps as a massively constructed — or, at least, geotechnically augmented and militarily amplified — terrain is quite heady, including the very idea that, in seeking to protect itself from outside invaders, Switzerland is prepared to dynamite, shell, bulldoze, and seal itself into a kind of self-protective oblivion, hiding out in artificially expanded rocky passes and concrete super-basements as all roads and bridges into and out of the country are instantly transformed into landslides and dust.